A lane change assistant is described in German Patent No. DE 101 14 470. A video system is provided as a sensor device using which the lane markings on the roadway and thus the lateral position of the host vehicle relative to the currently traveled lane may be detected. If the lateral position of the vehicle deviates from the lane center to one or the other side by more than a certain tolerance limit, an automatic regulating intervention in the steering takes place in order to return the vehicle approximately to the lane center. The driving comfort for the driver is thus considerably enhanced and traffic safety is also increased since the driver is able to pay full attention to the traffic situation. However, if the driver wants to change lanes intentionally, i.e., to initiate a passing process, he must exert greater forces on the steering wheel when the lane-keeping function is activated in order to overcome the forces caused by the regulating intervention of the lane-keeping assistant. For this reason, it is provided in the known system that the lane-keeping function is at least temporarily deactivated when a lane change intention of the driver is detected, e.g., when the turn signal is operated.
Moreover, a lane-keeping assistant for motor vehicles including a sensor device for detecting the lanes on the roadway, a control unit which exerts a force on the vehicle's steering via an actuator to hold the vehicle in the lane, and a device for detecting the lane change intention of the driver is described in German Patent No. DE 102 005 024382.7. The control unit is designed in such a way that, when a lane change intention is detected, the force exerted on the steering is modifiable asymmetrically in the sense of an easier lane change. Furthermore, in the event of a detected lane change intention from the host vehicle's lane to a target lane, the absolute value of the force exerted on the vehicle's steering is a function of the vehicle's deviation from a setpoint trajectory in such a way that the force for lateral positions between the setpoint trajectory on the host vehicle's lane and the setpoint trajectory on the target lane is decreased or equal to zero; however, it increases again beyond the setpoint trajectory of the target lane.